Familial Schwannomatosis: A Diagnostic Challenge

Cervical intranodal schwannoma - a rare diagnosis

Intranodal schwannoma is a rare benign tumor, which originates from the peripheral nerve sheath (Schwann cells), fewer cases being reported with lymphatic involvement. We present the case of a middle-aged female patient, with one-year growing mass in the lateral-cervical area, in intimate relation with the vascular package of the neck. Preoperative cervical computed tomography examination showed the tumor features. There was no intraoperative complication, with the piece being completely removed. The morphological examination revealed the structure of a lymph node, and after Hematoxylin-Eosin staining, there were eosinophilic cytoplasm, euchromatic nuclei, with round, elongated or slightly wavy form and reduced pleomorphism, rare degenerative nuclear atypia, and no mitotic activity nor necrosis. The expression of S100 protein on immunohistochemistry, along with negative results for smooth muscle actin and desmin sustained the diagnosis of intranodal schwannoma of the neck. With a low index of cellular proliferation (Ki67), this case is in line with the reported features of schwannoma having extremely rare malignant transformation.

The Secretomes of Painful Versus Nonpainful Human Schwannomatosis Tumor Cells Differentially Influence Sensory Neuron Gene Expression and Sensitivity

Schwannomatosis is a multiple tumor syndrome in which patients develop benign tumors along peripheral nerves throughout the body. The first symptom with which schwannomatosis patients often present, prior to discovery of tumors, is pain. This pain can be debilitating and is often inadequately alleviated by pharmacological approaches. Schwannomatosis-associated pain can be localized to the area of a tumor, or widespread. Moreover, not all tumors are painful, and the occurrence of pain is often unrelated to tumor size or location. We speculate that some individual tumors, but not others, secrete factors that act on nearby nerves to augment nociception by producing neuronal sensitization or spontaneous neuronal firing. We created cell lines from human SWN tumors with varying degrees of pain. We have found that conditioned medium (CM) collected from painful SWN tumors, but not that from nonpainful SWN tumors, sensitized DRG neurons, causing increased sensitivity to depolarization by KCl, increased response to noxious TRPV1 and TRPA1 agonists and also upregulated the expression of pain-associated genes in DRG cultures. Multiple cytokines were also detected at higher levels in CM from painful tumors. Taken together our data demonstrate a differential ability of painful versus non-painful human schwannomatosis tumor cells to secrete factors that augment sensory neuron responsiveness, and thus identify a potential determinant of pain heterogeneity in schwannomatosis.

Cervical Lymph Node Schwannoma-An Unexpected Diagnosis

INTRODUCTION

Schwannomas-Schwann cells-originating tumors-may develop in many locations. However, primary schwannomas arising within lymph nodes are extremely rare, with only a few cases described to this date in the English literature. For the intranodal location, most of the cases are described in the abdominal cavity. In these cases, clinicians may consider and check for familial disorders, such as neurofibromatosis type 2 (NF2) and schwannomatosis also called neurofibromatosis type 3. Schwannomas are benign neoplasms. Histologically, differential diagnosis for spindle-cell lesions in lymph nodes is important and must be done carefully, mainly because they may be attributable to metastatic disease. We report a case of a primary schwannoma arising in a cervical lymph node.

BACKGROUND

Primary schwannomas arising within lymph nodes are extremely rare, with only a few cases reported. Since they are benign neoplasms, the differential diagnosis with other intranodal spindle cell lesions, mostly malignant, is important.

METHODS

An asymptomatic 69-year-old woman, previously submitted to left hemithyroidectomy for a benign folicular nodule, underwent thyroidectomy totalization following the identification of a large thyroid nodule in routine evaluation.

RESULTS

Gross and microscopic examination and ancillary studies were consistent with the diagnosis of intranodal schwannoma. The patient had acquired bilateral hypoacusia. Therefore, type 2 neurofibromatosis was considered and vestibular schwannomas ruled out.

CONCLUSION

Herein, we present the second case of a primary schwannoma in a cervical lymph node reported so far. The relevance of the differential diagnosis is highlighted.